The use of different lifting arm arrangements for lifting a pipe has previously been described. The use of lifting cylinders to move the lifting arm arrangements has also previously been described.
Various documents describe systems for lifting pipes where a cylinder is used to carry out the lifting movement.
U.S. Pat. No. 4,765,401 describes a cylinder structure containing a piston having a throughgoing piston rod where a carriage carrying a torque wrench and a spinner is fastened to the piston rod. Movement of the piston in the cylinder structure results in horizontal movement of the carriage.
U.S. Pat. No. 4,081,084 describes a crane system for retrieving casings that are stored below deck. A carriage that travels along a track is used together with a hook system to move the casings. The hook elements move in and out of engagement with the ends of the casings using pistons that move in cylinders and thus move the carriages.
EP 0243993 and U.S. Pat. No. 2,871,743 describe pipe clamps and EP 0199664 describes a pipe handling machine equipped with carriages that are moved by the movement of a piston in a cylinder.
US 2006/104747, U.S. Pat. No. 4,696,207 and GB 1204864 describe background art of the present invention.